Mike asked:
Did the DOS version change to use long doubles or was it just the Xfractint version?
Jonathan needs to answer because he knows what he did. In my ignorance I would guess "DOS not Xfractint". Here's a related bit of information, derdged from my memory, so take it for what it's worth. An arcane fact is the math coprocessor in Intel chip did (and I believe, still does) math in 80 bit doubles. Virtually all modern OS's convert the 80 bit doubles to 64 bits when they get them out of the coprocessor, wasting the extra precision that in Fractint we value so highly. The old Microsoft compiler we are using for the DOS fractint has an 80 bit "long double" type which fits the math coprocessor floating point size. That means a fractal type calculation that uses long double gets the extra precision of 80 vs 64 bits with no speed penalty, since the calculation is already done at 80 bits anyway. This is one of the few areas where technology went backwards when the old segmented memory architecture was abandoned. At one point we actually tried to globally change "double" to "long double (meaning 80 bit double), and things kind of worked, but there were too many exceptions. We use typedefs for the types in Fractint so most of the same code can be used for DOS Fractint and Xfractint Somebody correct me if I am wrong, but I don't think the 80 bit double exists in the Linux world except under very unusual circumstances. long double is sometimes no different than double (64 bit). Hence my (guessed) answer to Mike's question. Tim